Sinusoidal laser scanner with optical filter

FIELD

p-0002The present invention relates generally to projection systems, and more specifically to scanning projection systems.

BACKGROUND

p-0003Scanning laser projectors typically scan a modulated laser beam in a raster pattern to display an image. Due to many possible factors, the resulting laser beam spot may traverse the raster pattern at a varying rate. For example, a sinusoidally scanned laser beam will produce a laser spot that traverses the raster pattern fastest near the center and slowest away from the center.

p-0004The varying rate of laser spot traversal may result in brightness variations in the displayed image. One way to combat these brightness variations is to increase resolution of analog-to-digital converters that drive laser light sources, but this increases cost.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0005<figref idrefs="DRAWINGS">FIG. 1</figref> shows a scanning laser projector in accordance with various embodiments of the present invention;

p-0006<figref idrefs="DRAWINGS">FIG. 2</figref> shows a raster pattern with brightness variations in accordance with various embodiments of the present invention;

p-0007<figref idrefs="DRAWINGS">FIGS. 3 and 4</figref> show scanning laser projectors in accordance with various embodiments of the present invention;

p-0008<figref idrefs="DRAWINGS">FIGS. 5 and 6</figref> show laser light sources with binary drivers in accordance with various embodiments of the present invention;

p-0009<figref idrefs="DRAWINGS">FIG. 7</figref> shows a flow diagram of methods in accordance with various embodiments of the present invention;

p-0010<figref idrefs="DRAWINGS">FIG. 8</figref> shows a block diagram of a mobile device in accordance with various embodiments of the present invention;

p-0011<figref idrefs="DRAWINGS">FIG. 9</figref> shows a mobile device in accordance with various embodiments of the present invention;

p-0012<figref idrefs="DRAWINGS">FIG. 10</figref> shows a head-up display system in accordance with various embodiments of the invention;

p-0013<figref idrefs="DRAWINGS">FIG. 11</figref> shows eyewear in accordance with various embodiments of the invention; and

p-0014<figref idrefs="DRAWINGS">FIG. 12</figref> shows a gaming apparatus in accordance with various embodiments of the present invention.

DESCRIPTION OF EMBODIMENTS

p-0015In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the scope of the invention. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled. In the drawings, like numerals refer to the same or similar functionality throughout the several views.

p-0016<figref idrefs="DRAWINGS">FIG. 1</figref> shows a scanning laser projector in accordance with various embodiments of the present invention. Scanning laser projector <b>100</b> includes image processing component <b>102</b>, multi-level digital-to-analog converter (DAC) <b>110</b>, light source(s) <b>112</b>, micro-electronic machine (MEMS) device <b>160</b> having scanning mirror <b>162</b>, and mirror drive circuits <b>116</b>. Scanning laser projector <b>100</b> also includes guiding optics <b>134</b>, <b>136</b>, and optical filter <b>170</b>.

p-0017In operation, image processing component <b>102</b> receives video data on node <b>101</b> and produces display pixel data used to drive light source(s) <b>112</b> when pixels are to be displayed. The video data on node <b>101</b> represents image source data that is typically received with pixel data on a rectilinear grid, but this is not essential. For example, video data on node <b>101</b> may represent a grid of pixels at any resolution (e.g., 640×480, 848×480, 1920×1080). Scanning laser projector <b>100</b> is a scanning projector that scans a raster pattern shown at <b>180</b>. The raster pattern does not necessarily align with the rectilinear grid in the image source data, and image processing component <b>102</b> operates to produce display pixel data that will be displayed at appropriate points on the raster pattern. For example, in some embodiments, image processing component <b>102</b> interpolates vertically and/or horizontally between pixels in the source image data to determine display pixel values along the scan trajectory of the raster pattern.

p-0018Multi-level DAC(s) <b>110</b> receive digital display pixel data from image processing component <b>102</b>, and produce an analog voltage or current to drive light source(s) <b>112</b>. The number of data bits received by DAC(s) <b>110</b> determines a maximum number of grayscale levels that can be produced by a single light source. For example, five bits results in a maximum of 32 grayscale levels. However, because of component variations (e.g., power supply voltages, laser diode luminance/current characteristics), and other variables, more data bits may be required to faithfully reproduce a given number of grayscale levels. For example, eight or ten bits might be required to faithfully reproduce 32 grayscale levels.

p-0019Light source(s) <b>112</b> receive the output from DAC(s) <b>110</b> and produce light having grayscale values in response thereto. Light source(s) <b>112</b> may be monochrome or may include multiple different color light sources. For example, in some embodiments, light source(s) <b>112</b> includes red, green, and blue light sources. In these embodiments, image processing component <b>102</b> outputs display pixel data corresponding to each of the red, green, and blue light sources.

p-0020In some embodiments, light source(s) <b>112</b> may include one or more laser light producing devices. For example, in some embodiments, the light source(s) <b>112</b> may include laser diodes. In these embodiments, light source(s) <b>112</b> may also include driver circuits that accept and/or condition drive signals. For example, driver circuits may include transimpedance amplifiers, coupling circuits, bias circuits, switches, and the like. The light from light source(s) <b>112</b> is directed to mirror <b>162</b> via guiding optics <b>134</b>, <b>136</b>. Any type of optical element may be included in the light path between light source(s) <b>112</b> and mirror <b>162</b>. For example, scanning laser projector <b>100</b> may include collimating lenses, dichroic mirrors, or any other suitable optical elements.

p-0021Scanning mirror <b>162</b> deflects on two axes in response to electrical stimuli received on node <b>193</b> from mirror drive circuits <b>116</b>. While moving on the two axes, scanning mirror <b>162</b> reflects light provided by light source(s) <b>112</b>. The reflected light sweeps a raster pattern and creates a resultant display at <b>180</b>. The shape of the raster pattern swept by scanning mirror <b>162</b> is a function of the mirror movement on its two axes. For example, in some embodiments, scanning mirror <b>162</b> sweeps in a first dimension (e.g., horizontal dimension) according to a sinusoidal stimulus, resulting in a substantially sinusoidal horizontal sweep. Also for example, in some embodiments, scanning mirror <b>162</b> sweeps in a second dimension (e.g., vertical dimension) in response to sawtooth wave stimulus, resulting in a substantially linear and unidirectional vertical sweep.

p-0022MEMS device <b>160</b> is an example of a scanning mirror assembly that scans light in two dimensions. In some embodiments the scanning mirror assembly includes a single mirror that scans in two dimensions (e.g., on two axes). Alternatively, in some embodiments, MEMS device <b>160</b> may be an assembly that includes two scan mirrors, one which deflects the beam along one axis, and another which deflects the beam along a second axis largely perpendicular to the first axis.

p-0023Optical filter <b>170</b> is placed in the light beam path after scanning mirror <b>162</b>. In some embodiments, optical filter <b>170</b> is characterized by a variable attenuation as a function of light position. For example, optical filter <b>170</b> may attenuate light less (or not at all) near the center of the filter, and attenuate light more near the edges of the filter. In some embodiments, the amount and gradient of attenuation may have an inverse relationship to brightness variations resulting from sinusoidal scanning. In this manner, optical filter <b>170</b> compensates for brightness variations due to sinusoidal scanning. Because an optical filter (rather than extra DAC bits) is compensating for brightness variations, the required number of DAC bits may be decreased, thereby reducing cost.

p-0024Optical filter <b>170</b> may provide the aforementioned compensation in the optical domain when placed anywhere in the beam path after scanning mirror <b>162</b>. For example, in some embodiments, optical filter <b>170</b> is placed in a beam exit window of a projection device. Also for example, in some embodiments, optical filter <b>170</b> is combined with another optical device such as a lens or other correction optic.

p-0025<figref idrefs="DRAWINGS">FIG. 2</figref> shows a raster pattern with brightness variations in accordance with various embodiments of the present invention. Raster pattern <b>180</b> is shown and described in <figref idrefs="DRAWINGS">FIG. 1</figref>. Although raster pattern <b>180</b> shows only a few horizontal sweeps for each vertical sweep, this is not a limitation of the present invention. For example, in some embodiments, hundreds or thousands of horizontal sweeps occur for each vertical sweep.

p-0026<figref idrefs="DRAWINGS">FIG. 2</figref> shows the horizontal direction as the “first dimension,” and the vertical direction as the “second dimension.” This is for naming convention purposes only, and a 90 degree rotation can result in the first dimension being the vertical direction and the second dimension being the horizontal direction.

p-0027Perceived brightness <b>210</b> represents the increased brightness near the left and right edges of the raster pattern prior to passing through optical filter <b>170</b>. As shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, this increased brightness may be a result of sinusoidal scanning in the first dimension. The increased brightness may occur, in part, because of increased pixel density as the scanned beam slows down near the left and right edges of raster pattern <b>180</b>.

p-0028Filter attenuation <b>220</b> represents the variable attenuation of optical filter <b>170</b> in the first dimension. In embodiments represented by <figref idrefs="DRAWINGS">FIG. 2</figref>, the filter attenuation <b>220</b> is substantially the inverse of the perceived brightness <b>210</b> in the first dimension. In some embodiments, optical filter <b>170</b> exhibits a uniform attenuation in the second dimension. In other embodiments optical filter <b>170</b> exhibits a variable attenuation in both the first and second dimensions. Optical filter <b>170</b> may exhibit any combination of varying and/or uniform attenuation in either or both of the first and second dimensions without departing from the scope of the present invention.

p-0029After the sinusoidally scanned light beam passes through optical filter <b>170</b>, the light beam exhibits a substantially uniform brightness across the raster pattern <b>180</b>.

p-0030Sinusoidal compensation provided by optical filter <b>170</b> may decrease the required number of data bits in DAC(s) <b>110</b>, thereby reducing cost. For example, without optical filter <b>170</b>, scanning laser projector <b>100</b> (<figref idrefs="DRAWINGS">FIG. 1</figref>) may include DACs with extra data bits to compensate for light variations in the first dimension due to sinusoidal scanning. The inclusion of optical filter <b>170</b> obviates the need for these extra DAC bits.

p-0031<figref idrefs="DRAWINGS">FIG. 3</figref> shows a scanning laser projector in accordance with various embodiments of the present invention. Scanning laser projector <b>300</b> is similar to laser projector <b>100</b> (<figref idrefs="DRAWINGS">FIG. 1</figref>) except that the DAC(s) <b>310</b> only convert a single bit of information for each light source.

p-0032Scanning laser projector <b>300</b> with single bit DAC(s) <b>310</b> is useful when the application requires only display of two levels for each color, such as is common with text on black background, or a head-up display (HUD) application, where a substantial amount of the display is expected to remain “see-through”. The light source driver need only provide an off state, and an on state, in which a constant drive value (voltage or current) is generated (a single bit DAC). In a color system that contains a red, blue, and green laser this still allows for generation of seven “colors” in addition to black.

p-0033Optical filter <b>170</b> allows operation of the sinusoidal laser scanning projector with a single bit DAC, in part because optical filter <b>170</b> obviates the need for extra DAC bits to compensate for brightness variations due to sinusoidal scanning.

p-0034<figref idrefs="DRAWINGS">FIG. 4</figref> shows a scanning laser projector in accordance with various embodiments of the present invention. Scanning laser projector <b>400</b> is similar to scanning laser projector <b>300</b> (<figref idrefs="DRAWINGS">FIG. 3</figref>), except that the DAC(s) and light source(s) are replaced by light source(s) with binary driver(s) <b>412</b>.

p-0035The binary driver(s) turn the light source(s) on and off in response to a single bit video signal received on node <b>403</b>. The binary drivers may include a single switch in series with light source such as a laser diode (see <figref idrefs="DRAWINGS">FIGS. 5 and 6</figref>), or may include any other mechanism to turn on and off a light source. A binary driver circuit is similar to a single bit DAC, but is potentially much simpler.

p-0036<figref idrefs="DRAWINGS">FIGS. 5 and 6</figref> show laser light sources with binary drivers in accordance with various embodiments of the present invention. Referring now to <figref idrefs="DRAWINGS">FIG. 5</figref>, light source <b>412</b>A is coupled in series with switch <b>510</b>. Light source <b>412</b>A is a current-driven light source. For example, in some embodiments, light source <b>412</b>A is a laser diode that produces light when current flows. Switch <b>510</b> is coupled in a current path between light source <b>412</b>A and a reference node. When switch <b>510</b> is open, no current flows, and light source <b>412</b>A is off. When switch <b>510</b> is closed, current flows, and light source <b>412</b>A is on. Accordingly, switch <b>510</b> functions as a binary driver that modulates light <b>412</b>A on and off.

p-0037Referring now to <figref idrefs="DRAWINGS">FIG. 6</figref>, light source <b>412</b>B is coupled in series with switch <b>610</b>. Light source <b>412</b>B is a current-driven light source. For example, in some embodiments, light source <b>412</b>B is a laser diode that produces light when current flows. Switch <b>610</b> is coupled in a current path between light source <b>412</b>B and power supply node <b>502</b>. When switch <b>610</b> is open, no current flows, and light source <b>412</b>B is off. When switch <b>610</b> is closed, current flows, and light source <b>412</b>B is on. Accordingly, switch <b>610</b> functions as a binary driver that modulates light <b>412</b>B on and off.

p-0038In some embodiments, the voltage on power supply node <b>502</b> is adjusted to cause the desired amount of current flow. The desired voltage may vary as the temperature of the light source varies and so may be adjusted over time. Various embodiments of the invention include control loops (not shown) to adjust the power supply voltage on node <b>502</b>.

p-0039<figref idrefs="DRAWINGS">FIG. 7</figref> shows a flow diagram of methods in accordance with various embodiments of the present invention. In some embodiments, method <b>700</b>, or portions thereof, is performed by a scanning laser projector, embodiments of which are shown in previous figures. In other embodiments, method <b>700</b> is performed by a series of circuits or an electronic system. Method <b>700</b> is not limited by the particular type of apparatus performing the method. Further, in some embodiments, some actions listed in <figref idrefs="DRAWINGS">FIG. 7</figref> are omitted from method <b>700</b>.

p-0040Method <b>700</b> is shown beginning with block <b>710</b>. As shown at <b>710</b>, a light beam is sinusoidally scanned in at least one dimension. In some embodiments, this corresponds to scanning mirror <b>162</b> scanning a light beam to create raster pattern <b>180</b>. In some embodiments, the light beam is scanned sinusoidally in one dimension, and in other embodiments, the light beam is scanned sinusoidally in two dimensions. Further, the light beam may be scanned sinusoidally by a first mirror, and then scanned sinusoidally or otherwise by a second mirror.

p-0041At <b>720</b>, the light beam is passed through an optical filter to variably attenuate the light beam as a function of position to compensate for brightness variations due to sinusoidal scanning. In some embodiments, this corresponds to optical filter <b>170</b> including variable attenuation characteristics as described with reference to <figref idrefs="DRAWINGS">FIG. 2</figref>.

p-0042<figref idrefs="DRAWINGS">FIG. 8</figref> shows a block diagram of a mobile device in accordance with various embodiments of the present invention. As shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, mobile device <b>800</b> includes wireless interface <b>810</b>, processor <b>820</b>, memory <b>830</b>, and scanning projector <b>801</b>. Scanning projector <b>801</b> paints a raster image at <b>180</b>. Scanning projector <b>801</b> is a scanning laser projector as described above with reference to previous figures. Scanning projector <b>801</b> includes optical filter <b>170</b> and may include multi-bit DAC(s), single bit DAC(s), or binary drivers as described herein.

p-0043Scanning projector <b>801</b> may receive image data from any image source. For example, in some embodiments, scanning projector <b>801</b> includes memory that holds still images. In other embodiments, scanning projector <b>801</b> includes memory that includes video images. In still further embodiments, scanning projector <b>801</b> displays imagery received from external sources such as connectors, wireless interface <b>810</b>, a wired interface, or the like.

p-0044Wireless interface <b>810</b> may include any wireless transmission and/or reception capabilities. For example, in some embodiments, wireless interface <b>810</b> includes a network interface card (NIC) capable of communicating over a wireless network. Also for example, in some embodiments, wireless interface <b>810</b> may include cellular telephone capabilities. In still further embodiments, wireless interface <b>810</b> may include a global positioning system (GPS) receiver. One skilled in the art will understand that wireless interface <b>810</b> may include any type of wireless communications capability without departing from the scope of the present invention.

p-0045Processor <b>820</b> may be any type of processor capable of communicating with the various components in mobile device <b>800</b>. For example, processor <b>820</b> may be an embedded processor available from application specific integrated circuit (ASIC) vendors, or may be a commercially available microprocessor. In some embodiments, processor <b>820</b> provides image or video data to scanning projector <b>801</b>. The image or video data may be retrieved from wireless interface <b>810</b> or may be derived from data retrieved from wireless interface <b>810</b>. For example, through processor <b>820</b>, scanning projector <b>801</b> may display images or video received directly from wireless interface <b>810</b>. Also for example, processor <b>820</b> may provide overlays to add to images and/or video received from wireless interface <b>810</b>, or may alter stored imagery based on data received from wireless interface <b>810</b> (e.g., modifying a map display in GPS embodiments in which wireless interface <b>810</b> provides location coordinates).

p-0046<figref idrefs="DRAWINGS">FIG. 9</figref> shows a mobile device in accordance with various embodiments of the present invention. Mobile device <b>900</b> may be a hand held projection device with or without communications ability. For example, in some embodiments, mobile device <b>900</b> may be a handheld projector with little or no other capabilities. Also for example, in some embodiments, mobile device <b>900</b> may be a device usable for communications, including for example, a cellular phone, a smart phone, a personal digital assistant (PDA), a global positioning system (GPS) receiver, or the like. Further, mobile device <b>900</b> may be connected to a larger network via a wireless (e.g., WiMax) or cellular connection, or this device can accept data messages or video content via an unregulated spectrum (e.g., WiFi) connection.

p-0047Mobile device <b>900</b> includes scanning projector <b>801</b> to create an image with light at <b>180</b>. Mobile device <b>900</b> also includes many other types of circuitry; however, they are intentionally omitted from <figref idrefs="DRAWINGS">FIG. 9</figref> for clarity.

p-0048Mobile device <b>900</b> includes display <b>910</b>, keypad <b>920</b>, audio port <b>902</b>, control buttons <b>904</b>, card slot <b>906</b>, and audio/video (A/V) port <b>908</b>. None of these elements are essential. For example, mobile device <b>900</b> may only include scanning projector <b>801</b> without any of display <b>910</b>, keypad <b>920</b>, audio port <b>902</b>, control buttons <b>904</b>, card slot <b>906</b>, or A/V port <b>908</b>. Some embodiments include a subset of these elements. For example, an accessory projector product may include scanning projector <b>801</b>, control buttons <b>904</b> and A/V port <b>908</b>.

p-0049Display <b>910</b> may be any type of display. For example, in some embodiments, display <b>910</b> includes a liquid crystal display (LCD) screen. Display <b>910</b> may always display the same content projected at <b>180</b> or different content. For example, an accessory projector product may always display the same content, whereas a mobile phone embodiment may project one type of content at <b>180</b> while displaying different content on display <b>910</b>. Keypad <b>920</b> may be a phone keypad or any other type of keypad.

p-0050A/V port <b>908</b> accepts and/or transmits video and/or audio signals. For example, A/V port <b>908</b> may be a digital port, such as a high definition multimedia interface (HDMI) interface, that accepts a cable suitable to carry digital audio and video data. Further, A/V port <b>908</b> may include RCA jacks to accept composite inputs. Still further, A/V port <b>908</b> may include a VGA connector to accept analog video signals. In some embodiments, mobile device <b>900</b> may be tethered to an external signal source through A/V port <b>908</b>, and mobile device <b>900</b> may project content accepted through A/V port <b>908</b>. In other embodiments, mobile device <b>900</b> may be an originator of content, and A/V port <b>908</b> is used to transmit content to a different device.

p-0051Audio port <b>902</b> provides audio signals. For example, in some embodiments, mobile device <b>900</b> is a media player that can store and play audio and video. In these embodiments, the video may be projected at <b>180</b> and the audio may be output at audio port <b>902</b>. In other embodiments, mobile device <b>900</b> may be an accessory projector that receives audio and video at A/V port <b>908</b>. In these embodiments, mobile device <b>900</b> may project the video content at <b>180</b>, and output the audio content at audio port <b>902</b>.

p-0052Mobile device <b>900</b> also includes card slot <b>906</b>. In some embodiments, a memory card inserted in card slot <b>906</b> may provide a source for audio to be output at audio port <b>902</b> and/or video data to be projected at <b>180</b>. Card slot <b>906</b> may receive any type of solid state memory device, including for example, Multimedia Memory Cards (MMCs), Memory Stick DUOS, secure digital (SD) memory cards, and Smart Media cards. The foregoing list is meant to be exemplary, and not exhaustive.

p-0053Control buttons <b>904</b> may be used for any purpose. For example, in some embodiments, control buttons <b>904</b> may be used to navigate a menu system on display <b>910</b>.

p-0054<figref idrefs="DRAWINGS">FIG. 10</figref> shows a head-up display system in accordance with various embodiments of the invention. Projector <b>801</b> is shown mounted in a vehicle dash to project the head-up display at <b>1000</b>. Although an automotive head-up display is shown in <figref idrefs="DRAWINGS">FIG. 10</figref>, this is not a limitation of the present invention. For example, various embodiments of the invention include head-up displays in avionics application, air traffic control applications, and other applications.

p-0055<figref idrefs="DRAWINGS">FIG. 11</figref> shows eyewear in accordance with various embodiments of the invention. Eyewear <b>1100</b> includes projector <b>801</b> to project a display in the eyewear's field of view. In some embodiments, eyewear <b>1100</b> is see-through and in other embodiments, eyewear <b>1100</b> is opaque. For example, eyewear <b>1100</b> may be used in an augmented reality application in which a wearer can see the display from projector <b>801</b> overlaid on the physical world. Also for example, eyewear <b>1100</b> may be used in a virtual reality application, in which a wearer's entire view is generated by projector <b>801</b>. Although only one projector <b>801</b> is shown in <figref idrefs="DRAWINGS">FIG. 11</figref>, this is not a limitation of the present invention. For example, in some embodiments, eyewear <b>1100</b> includes two projectors; one for each eye.

p-0056<figref idrefs="DRAWINGS">FIG. 12</figref> shows a gaming apparatus in accordance with various embodiments of the present invention. Gaming apparatus <b>1200</b> allows a user or users to observe and interact with a gaming environment. The game is navigated based on the motion, position or orientation of gaming apparatus <b>1200</b>, an apparatus that includes scanning laser projector <b>801</b>. Other control interfaces, such as manually-operated buttons, foot pedals, or verbal commands, may also contribute to navigation around, or interaction with the gaming environment. For example, in some embodiments, trigger <b>1242</b> contributes to the illusion that the user or users are in a first person perspective video game environment, commonly known as a “first person shooter game.” Because the size and brightness of the projected display can be controlled by the gaming application in combination with the user's movement, gaming apparatus <b>1200</b> creates a highly believable or “immersive” environment for these users.

p-0057Many other first person perspective simulations can also be created by gaming apparatus <b>1200</b>, for such activities as 3D seismic geo-prospecting, spacewalk planning, jungle canopy exploration, automobile safety instruction, medical education, etc. Tactile interface <b>1244</b> may provide a variety of output signals, such as recoil, vibration, shake, rumble, etc. Tactile interface <b>1244</b> may also include a touch-sensitive input feature, such as a touch sensitive display screen or a display screen that requires a stylus. Additional tactile interfaces, for example, input and/or output features for a motion sensitive probe are also included in various embodiments of the present invention.

p-0058Gaming apparatus <b>1200</b> may also include audio output devices, such as integrated audio speakers, remote speakers, or headphones. These sorts of audio output devices may be connected to gaming apparatus <b>1200</b> with wires or through a wireless technology. For example, wireless headphones <b>1246</b> provide the user with sound effects via a Bluetooth connection, although any sort of similar wireless technology could be substituted freely. In some embodiments, wireless headphones <b>1246</b> may include microphone <b>1245</b> or binaural microphone <b>1247</b>, to allow multiple users, instructors, or observers to communicate. Binaural microphone <b>1247</b> typically includes microphones on each ear piece, to capture sounds modified by the user's head shadow. This feature may be used for binaural hearing and sound localization by other simulation participants.

p-0059Gaming apparatus <b>1200</b> may include any number of sensors <b>1210</b> that measure distance, ambient brightness, motion, position, orientation, and the like. For example, gaming apparatus <b>1200</b> may detect absolute heading with a digital compass, and detect relative motion with an x-y-z gyroscope or accelerometer. In some embodiments, gaming apparatus <b>1200</b> also includes a second accelerometer or gyroscope to detect the relative orientation of the device, or its rapid acceleration or deceleration. In other embodiments, gaming apparatus <b>1200</b> may include a Global Positioning Satellite (GPS) sensor, to detect absolute position as the user travels in terrestrial space.

p-0060Gaming apparatus <b>1200</b> may include battery <b>1241</b> and/or diagnostic lights <b>1243</b>. For example, battery <b>1241</b> may be a rechargeable battery, and diagnostic lights <b>1243</b> could indicate the current charge of the battery. In another example, battery <b>1241</b> may be a removable battery clip, and gaming apparatus <b>1200</b> may have an additional battery, electrical capacitor or super-capacitor to allow for continued operation of the apparatus while the discharged battery is replaced with a charged battery. In other embodiments, diagnostic lights <b>1243</b> can inform the user or a service technician about the status of the electronic components included within or connected to this device. For example, diagnostic lights <b>1243</b> may indicate the strength of a received wireless signal, or the presence or absence of a memory card. Diagnostic lights <b>1243</b> could also be replaced by any small screen, such as an organic light emitting diode or liquid crystal display screen. Such lights or screens could be on the exterior surface of gaming apparatus <b>1200</b>, or below the surface, if the shell for this apparatus is translucent or transparent.

p-0061Other components of gaming apparatus <b>1200</b> may be removable, detachable or separable from this device. For example, the scanning laser projector may be detachable or separable from gaming housing <b>1249</b>. In some embodiments, the subcomponents of the scanning laser projector may be detachable or separable from gaming housing <b>1249</b>, and still function.

p-0062Although the present invention has been described in conjunction with certain embodiments, it is to be understood that modifications and variations may be resorted to without departing from the scope of the invention as those skilled in the art readily understand. Such modifications and variations are considered to be within the scope of the invention and the appended claims.